After months of stonewalling, Facebook founder Mark Zuckerberg agreed to turn over more than 3,000 Russian-linked political ads that ran during last year’s election campaign to Congress.

In his remarks, made in a Facebook Live post from his personal account, Zuckerberg said the company “recently uncovered this activity” and began cooperating with investigators looking at Russian attempts to influence the 2016 presidential election.

“We are actively working with the US government on its ongoing investigations into Russian interference,” Zuckerberg said. “We have been investigating this for many months, and for a while we had found no evidence of fake accounts linked to Russia running ads. When we recently uncovered this activity, we provided that information to the special counsel. We also briefed Congress, and this morning I directed our team to provide the ads we've found to Congress as well.”

ABC News has learned that Zuckerberg called Sen. Mark Warner, D-Va, vice chair of the Senate Intelligence Committee, personally on Thursday to tell him of the company’s decision to offer more information to Congress.